The mother of the Boston Marathon bombing suspects has said she does not believe her sons carried out the attack and were framed by the authorities.
Zubeidat Tsarnaeva said she regretted moving to the United States and claimed "America took my kids away from me".
An emotional Mrs Tsarnaeva said she was told her she could not see her 19-year-old son Dzhokhar Tsarnaev, who is in hospital where US officials said he is being questioned by investigators.
She said: "They already told us that they are never going to show us Dzhokhar even if we come there, until he will be put into their jail we wouldn't be able to see him."
She said her sons were "nice boys" who "loved each other", and said they had been happy in America and had plenty of friends.
Mrs Tsarnaeva said the family had moved to the US because she thought "America was going to protect us".
She said Dzhokhar's lawyers had said that investigators had not started to question her son because he was not well enough.
She said she had been told he had a "really bad wound to his right neck" which meant he could not eat and was being fed by a tube.
Reports in the US have claimed the teenager suffered a self-inflicted throat injury during a shoot-out and subsequent stand-off with the police.
According to US officials, he said his brother Tamerlan, 26, who died in a gunfight with police, recruited him to take part in the attacks only recently.
However, both Mrs Tsarnaeva and her husband Anzor Tsarnaev said there was no way their sons were responsible for the attack which killed three people, including an eight-year-old boy, and injured more than 180 others.
She said her sons were victims of a conspiracy and had been framed. She claimed she had seen a video of Tamerlan being arrested and was later shown pictures of him alive.
Mrs Tsarnaeva said she had spoken to her son after the bombings and before he was killed in the police shoot-out during which he told her "Don't worry mamma" and tried to reassure her he was safe.
Mr Tsarnaev told reporters: "I am going to the United States. I want to say that I am going there to see my son, to bury the older one. I don't have any bad intentions. I don't plan to blow up anything."
Banging the table as he spoke, he said: "I am not angry at anyone. I want to go find out the truth."
Mrs Tsarnaeva said she was not sure whether she would accompany her husband. She was charged with shoplifting in the US last summer and is concerned she could be arrested.
They were speaking as it emerged that Tamerlan's name had been included on a database of suspected terrorists by the CIA in 2011, 18 months before the attacks.
He was investigated after Russia's FSB security service raised concerns that he had become a follower of Russian Islam.
Mrs Tsarnaeva said she did not believe that Russia had raised concerns over her son with the US authorities.
The press conference came as Russian President Vladimir Putin gave his annual question-and-answer session during which he said the Boston bombings showed the need for closer cooperation between Moscow and Washington.
He said: "We always have said that we shouldn't limit ourselves to declarations about terrorism being a common threat and engage in closer cooperation.
"Now these two criminals have proven the correctness of our thesis."
Mr Putin also criticised the West for refusing to declare Chechen militants terrorists and offering them political assistance in the past.
He said: "I always felt indignation when our Western partners and Western media were referring to terrorists who conducted brutal and bloody crimes on the territory of Russia as rebels."